In order to reduce the operating cost of a network system of a business operator, a technique called NFV (Network Functions Virtualization) that implements some of network functions, which have been implemented by using a dedicated device, by using a virtual machine of a general-purpose server device is used.
A technique that controls a virtual machine of a general-purpose server device is implemented as a network system control device and a network system control scheme for a data center cloud, and this is applied to a network system control device and a network system control scheme for NFV.
The connection between virtual machines is made by setting a virtual link called a path in a relay device on a route that connects between the virtual machines. The path is uniquely recognized by combination of various protocol addresses in order to avoid interference of communication between paths.
Generally, a network system of a business operator includes administrative domains that are separated by areas or roles and is constructed and managed for each administrative domain. In each administrative domain, a point control device, which is a device that manages and controls devices in the administrative domain, is located. Further, there is a case where a network system of a business operator uses a plurality of administrative domain devices in order to provide a service using the network system, and in this case, an integrated control device, which is a network system control device that integrates and manages a plurality of point control devices in order for device control to provide services, is located. Note that the integrated control device may manage a point control device that is located in a network system of another network operator or a data center operator.
As a specific method to construct a network, there is a technique that, based on the assumption that devices constituting a network are connected in a hierarchy, allocates available addresses to terminal devices based on topology information containing hierarchy information (for example, see Patent Literature 1).